Optical sorters are routinely used in processing plants to remove contaminants and/or defects from a variety of agricultural commodities e.g., tree nuts, peanuts, fruits, vegetables, and grain. Modem commercially available sorting equipment typically measures reflectance from a sample at two wavelengths, either in the visible, or near infrared (NIR) regions of the electromagnetic spectrum. The outputs of photodiode based detectors are input into a computer, or the equivalent i.e., any microprocessor based device, either for mapping and algorithm parameterization in the training process, or for classification during sorting (see e.g., Bee and Honeywood, (2004) In “Detecting foreign bodies in food”, Chapter 6. Edited by M. Edwards).
Most modern commercially available sorting devices are not designed for optimal sorting of any particular defect or commodity, but instead are designed to be adaptable to many different sorting tasks through training (see e.g., Haff and Pearson, (2006) Trans. ASABE 49(4): 1105-1113). Thus, the typical computer based sorting equipment is sophisticated, but is often unnecessarily complex for simple sorting tasks. Moreover, modem computer based sorting equipment is expensive. Indeed, new units typically cost upward of $100,000.
Unfortunately, despite the sophistication and cost, computer/micro-processor based sorting devices are often unable to achieve the quality standards mandated by consumers or regulatory agencies for a product. Thus, manual inspection of the product is also frequently required. The high cost of manual labor and the expensive sorting equipment burdens agricultural producers with high costs. Naturally, the high cost of producing a product is passed on to consumers, and high cost may ultimately limit sales.
Clearly then, commodity producers as well as consumers stand to benefit from quality, well sorted product at lower prices. Thus, what is needed in the art is an alternative to the expensive computer/micro-processor based sorting equipment currently in use. Fortunately, as will be clear from the following disclosure, the present invention provides for this and other needs.